1. Field of the Invention
The present invention relates to a magazine conveying apparatus that transfers one magazine at a time from a magazine stand to a magazine receiver of an elevator means.
2. Prior Art
FIG. 6a-f shows one of the conventional devices for conveying magazines that stores electronic devices such as semiconductors, etc. in the vertically arranged accommodation sections provided therein.
As shown in FIG. 6(a), the elevator 10 of the conveying device has a slider 12 that is engaged with a screw 11. When the screw 11 is rotated, the slider 12 is moved up and down. The slider 12 has a magazine receiver 13.
A magazine stand 14 that carries magazines 1 and 2 thereon is installed in front of the elevator 10, i.e., on the left side of the elevator 10 in the drawing. The magazine stand has an open space in the middle, and two sets of magazine receivers 15 and 16 are installed in the open space of the magazine stand 14. The magazine receivers 15 and 16 are installed on a U-shaped arm 17 which is moved up and down and also moved to the right and left by a driving means (not shown).
As shown in FIG. 6(f), the conveying device further includes a conveyor 21 installed above the magazine stand 14 to convey a workpiece 20. Magazine guide rails 22 for stabilizing the magazines, that are lifted by the magazine receiver 13, are installed above the magazine receiver 13. In addition, a clamper 23 is installed on the magazine guide rails 22. The clamper 23 holds the magazines which are filled with workpiece 20 or from which the workpieces 20 have been fed out.
In operation, as shown in FIG. 6(a), two magazines 1 and 2 are placed at two predetermined positions on the magazine stand 14. Then, as shown in FIG. 6(b), the arm 17 is raised to lift the magazines 1 and 2, and as shown in FIG. 6(c), the arm 17 is moved to the right (in the drawing) so that the first magazine 1 is positioned above the magazine receiver 13. Next, as shown in FIG. 6(d), the arm 17 is lowered, letting the magazine 1 be on the magazine receiver 13, and as shown in FIG. 6(e), the arm 17 moves to the left and returns to a waiting position. After this, as shown in FIG. 6(f), the screw 11 is rotated to raise the magazine receiver 13 until the uppermost accommodating section of the magazine 1 is positioned at the level of the conveying surface of the conveyor 21. The workpiece 20 on the conveyor 21 is brought into the magazine 1 or a workpiece inside the uppermost accommodating section of the magazine 1 is fed out onto the conveyor 21.
Each time the workpiece 20 is brought into the magazine or fed out from the magazine, the magazine is raised by one pitch so that the next accommodation section of the magazine comes to the height level of the conveyor 21. If the magazine is filled with the workpieces 20, or if all the workpieces 20 have been fed out from the magazine 1, then the magazine receiver 13 is raised, and the magazine 1 is temporarily held by the clamper 23 (until the next magazine is sent to the conveyor 21). Afterward, the magazine receiver 13 is lowered in order to receive the next magazine 2, and a new magazine 3 is placed on the magazine stand 14 for the next transfer operation.
In this prior art device, the arm 17 transfers the magazines to the magazine receiver 13 of the elevator 10 by repeating the vertical and horizontal movements. Accordingly, only a small number of magazines are placed on the magazine stand 14. In addition, the positions where the magazines 1 and 2 are placed are limited (only two), and positioning errors are easily made by the operator. Moreover, if the size of the magazines changes, the magazine receivers 15 and 16 must be changed accordingly (in the space distance, etc.).